Trunnion assembly

ABSTRACT

A trunnion assembly for the paddle shaft of a mortar mixer including a substantially cylindrical drum having end plates includes a housing, having an interior space defined by an interior surface around the shaft. A first seal is located adjacent the end plate and is positioned around the shaft and is mounted between such shaft and the interior surface. A second seal is spaced outwardly from the first seal and positioned around the shaft between the shaft and the affixed interior surface. The first and second seals partition a portion of the interior space to define a first chamber for carrying grease. The second seal is spaced away from a shaft bearing to partition a second portion of the interior space to define a second chamber for carrying grease which forms a positive seal to prevent contaminated grease from entering the bearing when the first chamber is purged of contaminated grease.

CROSS REFERENCE TO RELATED APPLICATION

Not Applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

REFERENCE TO A MICROFICHE APPENDIX

Not Applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to seals for trunnions and particularly toseals for trunnions used in mortar mixing drums.

2. Relevant Art

Trunnions used in mortar mixing drums employ sealing apparatus includinga single set of resilient seals with lips biased against the paddleshaft and facing the interior space of the drum. A single grease chamberis formed by and positioned outwardly of the set of seal, away from thedrum. Conventional trunnions allow contaminated grease to be pushedoutwardly into the trunnion/shaft bearing area as the seal/shaftinterface shows wear and tear over a period of time. What is desired isa sealing system that increases the protection of the shaft bearing.

BRIEF SUMMARY OF THE INVENTION

In one aspect of the present invention there is provided a trunnionassembly for a mortar mixer including a substantially cylindrical drumhaving end plates and an elongate paddle shaft mounted horizontally andextending into a bearing through each drum end plate into a bearingcarried by the trunnion assembly, trunnion assembly comprising a housinghaving an interior space defined by an interior surface around suchshaft, a first seal means adjacent an end plate and positioned aroundsuch shaft. First mounting means affixes the first seal means betweensuch shaft and the interior surface and a second seal means spacedoutwardly from the first seal is positioned around such shaft. Secondmounting means provides for affixing the second seal between such shaftand the interior surface, the first and second seal means partitioning aportion of the interior space to define a first chamber for carryinggrease and the second seal means being spaced away from a shaft bearingto partition a second portion of the interior space to define a secondchamber for carrying grease. The first seal means includes a pluralityof resilient seal elements, each seal element having one end portion incontact with such shaft. The second seal means includes a singleresilient seal element having one end portion in contact with suchshaft. The second seal means includes a single resilient seal elementhaving one end portion in contact with such shaft. The second seal meansincludes a resilient seal element having one end portion in contact withsuch shaft. The housing includes a first second passageway into theinterior space for supplying grease into respective first and secondchambers.

In another aspect of the present invention there is provided a pair oftrunnion assemblies for the paddle shaft of a mortar mixer including asubstantially cylindrical drum having end plates, each trunnion assemblycomprising a housing, the housing having an interior space defined by aninterior surface around such shaft. A first seal means is adjacent anend plate positioned around such shaft and a first mounting meansprovides for affixing the first seal means between such shaft and theinterior surface. A second seal means is spaced outwardly form the firstseal and positioned around such shaft and second mounting means foraffixing the second seal between such shaft and the interior surface.The first and second seal means partitions a portion of the interiorspace to define a first chamber for carrying grease, the second sealmeans being spaced away from a shaft bearing to partition a secondportion of the interior space to define a second chamber for carryinggrease. The first seal means includes a plurality of resilient sealelements, each having one end portion in contact with such shaft. Thesecond seal means includes a single resilient seal element having oneend portion in contact with such shaft.

Second seal means includes a resilient seal element having one endportion in contact with such shaft. The housing includes a first andsecond passageway into the interior space for supplying grease intorespective first and second chambers.

Another aspect of the present invention provides an improved trunnionassembly that includes a housing including a first and second endportion and an interior spaced defined by an interior surface for ashaft and a bearing mounted in the second end portion for such shaft,the improvement comprising a first seal means adjacent the first endportion and positioned around such shaft, the first seal means includingat least one first seal element and mounting means for mounting the atleast one seal element to the interior surface and in contact with suchshaft. A second seal means is spaced away from the first seal meansincluding a least one second seal element and mounting means formounting the at least one second seal element to the interior surfaceand in contact with such shaft, a portion of the interior space betweenthe at least one first seal element and the at least one second sealelement defining a first chamber for carrying lubricating materialtherein and a portion of the interior space between the at least onesecond seal element and a bearing mounted in the end portion defining asecond chamber for carrying lubricating material therein. The first sealmeans includes a plurality of resilient seal elements each having oneend portion in contact with such shaft. The second seal means includes asingle resilient seal element having one end portion in contact withsuch shaft.

Second seal means includes a first and second passageway into theinterior space for supplying grease into respective first and secondchambers.

The present invention also provides improved rotatable trunnionassemblies for a rotatable mixing apparatus, each trunnion assemblyincluding a first and second end portion and an interior space definedby an interior surface for a shaft and a bearing mounted in the secondend portion for such shaft, the improvement comprising a first sealmeans adjacent the first end portion and positioned around such shaft.The first seal means includes at least two first seal elements andmounting means for mounting each first seal element to the interiorsurface and in contact with such shaft, a second seal means spaced awayfrom the first seal means including at least one second seal element andmounting means for mounting the at least one second seal element to theinterior surface and in contact with such shaft. A portion of theinterior space between the at least one first seal element and the atleast one second seal element defining a first chamber for carryinglubricating material therein, a portion of the interior space betweenthe at least one second seal element and a bearing mounted in the endportion defining a second chamber for carrying lubricating materialtherein. The first seal means includes three resilient seal elements,each having one end portion in contact with such shaft. The second sealmeans includes a single resilient seal element having one end portion incontact with such shaft. Each first seal element includes a resilientseal member having one end portion in contact with such shaft. Thehousing includes a first and second passageway into the interior spacefor supplying grease into the respective first and second chambers.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The novel features which are believed to be characteristic of thisinvention are set forth with particularity in the appended claims. Theinvention itself, however, both as to its organization and method ofoperation, together with further objects and advantages thereof, maybest be understood by reference to the following description, taken inconnection with the accompanying drawings, in which:

FIG. 1 is a cross-sectional pictorial view of a trunnion employing atwin grease chamber system in accord with the present invention;

FIG. 2 is a cross-sectional pictorial view of another embodiment of thetrunnion and sealing system in accord with the present invention; and

FIG. 3 is a cross-sectional pictorial view of another embodiment of thetrunnion and sealing system in accord with the present invention.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

Introduction

Mortar and plaster mixers provide a seal and a grease chamber. Due towear and tear, the mortar slurry may enter into the trunnion housing andtravel into the shaft bearing. When grease is pumped into the greasechamber in an effort to purge the contaminated grease into the mixerdrum, the contaminated grease may be forced into the bearing areathereby damaging the mixing apparatus.

The present design utilizes two grease chambers and seals:

A single seal with two metal support washers forms the first outergrease chamber and is back loaded into the trunnion with the seal lip onthe paddle shaft facing the drum and held in position by a lockingcollar. A side hole in the locking collar must be lined up with thethreaded hole where the Zerk fitting is screwed in. This alignment willallow grease to flow through the collar and into this chamber while thelocking collar holds the rubber seal between two metal washers in thecorrect position. When fresh grease is forced into this chamber, the oldgrease will be purged either into the front chamber or exit through thedrum bearing area.

A triple seal completes the second inner grease chamber closest to thedrum and is front loaded into the trunnion housing with all three sealslips on the paddle shaft facing into the mixer's drum. These three sealsare held in position by trunnion mounting bolts. Because the chamber hasa positive outer seal, the fresh grease can now push all thecontaminated grease back into the mixers drum when the grease is forcedinto the inner chamber.

With respect now to the drawings, a trunnion assembly is illustrated inFIG. 1 at numeral 10. A paddle shaft 11 is mounted in interior space 13in trunnion housing 12. A first set of drum seals 14 is held in place atthe front (inward portion) of housing 12 via metal support fitting 15.The seals 14 are mounted to orient lips 14′ toward the interior space 16of the mixer drum.

The drum seal includes inner grease storage chamber 17, a second drumseal 18 held in place via metal fitting 19 with seal lip 18′ orientedtowards the front of the assembly housing 12. Grease is supplied tochamber 17 via Zerk grease fittings 21 and 25 and passageways 22 and 26respectively. The seals 14 and 18 partition a portion of interior space13. The shaft bearing seal protects the bearing assembly 27 positionedvia snap ring 27′ and includes outer grease chamber 20 that is suppliedvia Zerk grease fitting 23 and passageway 24.

Snap ring 30 is mounted in groove 30′ adjacent channel 31 into whichfitting 19 is mounted to hold fitting 19/seal 18 in place. Inner seals14 and fitting 15 are mounted into channel 32 formed by housing 12 anddrum end plate 29.

Grease forced into the inner grease chamber 17 exits inwardly into druminterior space 16 because of the positive outer seal provide by seal 18and filled chamber 20.

Trunnion 10 is secured to end plate 29 of the mixing drum via aplurality of bolts 28 as needed.

An alternate embodiment of the trunnion is illustrated at 33 in FIG. 2.The trunnion housing 34 provides shaft passageway 39 into drum interior38 to provide an outer grease storage chamber 46 smaller than chamber 20and an inner grease chamber 40 that is larger than chamber 17.

The first set of seals 35 is substantially the same as described aboveregarding FIG. 1. Support fitting 36 fits into channel 43, whichincludes a portion of drum end plate 37. Outer seal 41 is mounted viafitting 42 that is seated into channel 44 that is completed by ring 45and forms grease chamber 46. Shaft bearing 47 is protected fromcontamination by chamber 46. Shaft bearing 47 is protected fromcontamination by chamber 46. Zerk fittings 48 and 50 provide grease viarespective passageways 49 and 51. Ring 45 includes an opening 52 that isaligned with the passageway 51.

In FIG. 3 another embodiment of the trunnion 53 in accord with thepresent invention is shown. Trunnion housing 54 provides passageway 63for paddle shaft 62. Trunnion 53 is mounted to end plate 59, partlydefining interior space 60, via bolts 61.

The inner, first set of drum seals 55 includes two elements secured viametal spacer fittings 56 against shaft 62 (mounted in passageway 63) asdescribed hereinabove. An outer, second set of drum seals 57 includestwo elements secured into place via metal spacer fittings 58. Metalbolts 61 secure drum end plate 59 to trunnion 53. Trunnion housing 54 isformed to provide a channel 70 into which seals 55 and 57 and fittings56 and 58 are mounted and secured via bolts 61 therethrough.

Zerk fittings 65 and 67 and associated passageways 66 and 68respectively provide grease into first inner grease chamber 64 which isdefined by the space between the seal sets 55 and 57 and respectivesecond outer grease chamber 69 defined between seal set 57 and shaftbearing assembly 71.

The specific embodiment of FIGS. 1-3 chosen in a particular applicationdepends on the size of the associated mixing drum and the speed andloading on the paddle shaft which itself contributes to the choice ofshaft bearing used.

In summary, the present trunnion is attached to the drum by four ½″bolts. The mixers are “dry cleaned” daily with a mason's hammer and thedrum's end plate can become deformed, Thus four spaced ½″ bolts insteadof three {fraction (5/16)}, or four ⅜′, to minimize deformity of theplate adjacent trunnion attachment.

The present trunnion also employs a vinyl cover to protect the trunnionfrom mortar splash. Such cover also protects the Zerks from becomingencased in mortar.

By protecting the paddle shaft bearing with its own unique chamber offresh grease that cannot be contaminated with mortar slurry from thedrum, the life of the bearing is greatly extended at minimum expense.When a bearing fails the paddle shaft drops because it has lost itsdesigned support tolerance and then severe consequential damage occursas the paddles begin to rub and then cut into the drum. This designimprovement affords definite bearing life extension and properfunctioning of the mixers.

The “side by side” grease chambers are also unique. The outside greasechamber or “the bearing grease chamber”, when pressurized with grease isfed in two directions into the paddle with grease can field in only onedirection, back into the drum, thus providing the ability to purge thisgrease chamber of all contaminated grease, and extending the life of thedrum seals. The contaminated grease is forced back into the drum andnever backwards into the bearing as is the case in most mixer designs.

All the seal lips in the improved trunnion face toward the interiorspace of the drum.

While the invention has been described with respect to certain specificembodiments, it will be appreciated that many modifications and changesmay be made by those skilled in the art without departing from thespirit of the invention. It is intended therefore, by the appendedclaims to cover all such modifications and changes as fall within thetrue spirit and scope of the invention.

1. A trunnion assembly for a mortar mixer including a substantiallycylindrical drum having end plates and an elongate paddle shaft mountedhorizontally and extending into a bearing through each drum end plateinto a bearing carried by said trunnion assembly, said trunnion assemblycomprising a housing, said housing having an interior space defined byan interior surface around such shaft, a first seal means adjacent anend plate and positioned around such shaft, first mounting means foraffixing said first seal means between such shaft and said interiorsurface, a second seal means spaced outwardly from said first seal andpositioned around such shaft, second mounting means for affixing saidsecond seal between such shaft and said interior surface, said first andsecond seal means partitioning a portion of said interior space todefine a first chamber for carrying grease, said second seal means beingspaced away from a shaft bearing to partition a second portion of saidinterior space to define a second chamber for carrying grease, saidhousing including a first grease passageway for providing grease intosaid first chamber and a second grease passageway spaced away from saidfirst grease passageway for providing grease into said second chamber.2. The trunnion assembly as defined in claim 1 wherein said first sealmeans includes a plurality of resilient seal elements, each said sealelement having one end portion in contact with such shaft.
 3. Thetrunnion assembly as defined in claim 2 wherein said second seal meansincludes a single resilient seal element, said single seal elementhaving one end portion in contact with such shaft.
 4. The trunnionassembly as defined in claim 1 wherein said second seal means includes aresilient seal element, said seal element having one end portion incontact with such shaft.
 5. (canceled)
 6. A pair of trunnion assembliesfor the paddle shaft of a mortar mixer including a substantiallycylindrical drum having end plates, each said trunnion assemblycomprising a housing, said housing having an interior space defined byan interior surface around such shaft, a first seal means adjacent anend plate and positioned around such shaft, first mounting means foraffixing said first seal means between such shaft and said interiorsurface, a second seal means spaced outwardly from said first seal andpositioned around such shaft, second mounting means for affixing saidsecond seal between such shaft and said interior surface, said first andsecond seal means partitioning a portion of said interior space todefine a first chamber for carrying grease, said second seal means beingspaced away from a shaft bearing to partition a second portion of saidinterior space to define a second chamber for carrying grease, each saidhousing including a pair of spaced grease fittings, a first passagewaycommunicating between one of said grease fittings and said first chamberand a second passageway communicating between another said greasefittings and said second chamber.
 7. The trunnion assemblies as definedin claim 6 wherein said first seal means includes a plurality ofresilient seal elements, each said seal element having one end portionin contact with such shaft.
 8. The trunnion assemblies as defined inclaim 7 wherein said second seal means includes a single resilient sealelement, said single seal element having one end portion in contact withsuch shaft.
 9. The trunnion assemblies as defined in claim 6 whereinsaid second seal means includes a resilient seal element, said sealelement having one end portion in contact with such shaft. 10.(canceled)
 11. An improved trunnion assembly that includes a housingincluding a first and second end portion and an interior spaced definedby an interior surface for a shaft and a bearing mounted in said secondend portion for such shaft, the improvement comprising a first sealmeans adjacent said first end portion and positioned around such shaft,said first seal means including at least one first seal element andmounting means for mounting said at least one seal element to saidinterior surface and in contact with such shaft, a second seal meansspaced away from said first seal means including at least one secondseal element and mounting means for mounting said at least one secondseal element to said interior surface and in contact with such shaft, aportion of said interior space between said at least one first sealelement and said at least one second seal element defining a firstchamber for carrying lubricating material therein, a portion of saidinterior space between said at least one second seal element and abearing mounted in said end portion defining a second chamber forcarrying lubricating material therein, said housing including a firstgrease fitting and a first passageway communicating between said firstgrease fitting and said first chamber and a second grease fitting spacedaway from said first grease fitting and a second passageway spaced awayfrom said first passageway communicating between said second greasefitting and said second chamber.
 12. The trunnion assembly as defined inclaim 11 wherein said first seal means includes a plurality of resilientseal elements, each said seal element having one end portion in contactwith such shaft.
 13. The trunnion assembly as defined in claim 12wherein said second seal means includes a single resilient seal element,said single seal element having one end portion in contact with suchshaft.
 14. The trunnion assembly as defined in claim 11 wherein saidsecond seal means includes a resilient seal element, said seal elementhaving one end portion in contact with such shaft.
 15. (canceled) 16.Improved trunnion assemblies for a rotatable mixing apparatus, eachtrunnion assembly including a housing including a first and second endportion and an interior space defined by an interior surface for a shaftand a bearing mounted in said second end portion for such shaft, theimprovement comprising a first seal means adjacent said first endportion and positioned around such shaft, said first seal meansincluding at least two first seal elements and mounting means formounting each said first seal element to said interior surface and incontact with such shaft, a second seal means spaced away from said firstseal means including at least one second seal element and mounting meansfor mounting said at least one second seal element to said interiorsurface and in contact with such shaft, a portion of said interior spacebetween said at least one first seal element and said at least onesecond seal element defining a first chamber for carrying lubricatingmaterial therein, a portion of said interior space between said at leastone second seal element and a bearing mounted in said end portiondefining a second chamber for carrying lubricating material therein,each said housing including a pair of spaced grease fittings and a pairof elongated spaced passageways respectively connected with said firstand second chambers.
 17. The trunnion assemblies as defined in claim 16wherein said first seal means includes three resilient seal elements,each said seal element having one end portion in contact with suchshaft.
 18. The trunnion assemblies as defined in claim 17 wherein saidsecond seal means includes a single resilient seal element, said singleseal element having one end portion in contact with such shaft.
 19. Thetrunnion assemblies as defined in claim 16 wherein each said first sealelement includes a resilient member, said member having one end portionin contact with such shaft.
 20. (canceled)